/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.apache.tomcat.jni;

/**
 * Proc
 *
 * @author Mladen Turk
 */
public class Proc {

	/*
	 * apr_cmdtype_e enum
	 */
	public static final int APR_SHELLCM = 0;
	/**
	 * use the shell to invoke the program
	 */
	public static final int APR_PROGRAM = 1;
	/**
	 * invoke the program directly, no copied env
	 */
	public static final int APR_PROGRAM_ENV = 2;
	/**
	 * invoke the program, replicating our environment
	 */
	public static final int APR_PROGRAM_PATH = 3;
	/**
	 * find program on PATH, use our environment
	 */
	public static final int APR_SHELLCMD_ENV = 4;
	/**
	 * use the shell to invoke the program,
	 * replicating our environment
	 */

    /*
     * apr_wait_how_e enum
     */
	public static final int APR_WAIT = 0;
	/**
	 * wait for the specified process to finish
	 */
	public static final int APR_NOWAIT = 1;
	/**
	 * do not wait -- just see if it has finished
	 */

    /*
     * apr_exit_why_e enum
     */
	public static final int APR_PROC_EXIT = 1;
	/**
	 * process exited normally
	 */
	public static final int APR_PROC_SIGNAL = 2;
	/**
	 * process exited due to a signal
	 */
	public static final int APR_PROC_SIGNAL_CORE = 4;
	/**
	 * process exited and dumped a core file
	 */

	public static final int APR_NO_PIPE = 0;
	public static final int APR_FULL_BLOCK = 1;
	public static final int APR_FULL_NONBLOCK = 2;
	public static final int APR_PARENT_BLOCK = 3;
	public static final int APR_CHILD_BLOCK = 4;

	public static final int APR_LIMIT_CPU = 0;
	public static final int APR_LIMIT_MEM = 1;
	public static final int APR_LIMIT_NPROC = 2;
	public static final int APR_LIMIT_NOFILE = 3;

	/**
	 * child has died, caller must call unregister still
	 */
	public static final int APR_OC_REASON_DEATH = 0;
	/**
	 * write_fd is unwritable
	 */
	public static final int APR_OC_REASON_UNWRITABLE = 1;
	/**
	 * a restart is occurring, perform any necessary cleanup (including
	 * sending a special signal to child)
	 */
	public static final int APR_OC_REASON_RESTART = 2;
	/**
	 * unregister has been called, do whatever is necessary (including
	 * kill the child)
	 */
	public static final int APR_OC_REASON_UNREGISTER = 3;
	/**
	 * somehow the child exited without us knowing ... buggy os?
	 */
	public static final int APR_OC_REASON_LOST = 4;
	/**
	 * a health check is occurring, for most maintenance functions
	 * this is a no-op.
	 */
	public static final int APR_OC_REASON_RUNNING = 5;

    /* apr_kill_conditions_e enumeration */
	/**
	 * process is never sent any signals
	 */
	public static final int APR_KILL_NEVER = 0;
	/**
	 * process is sent SIGKILL on apr_pool_t cleanup
	 */
	public static final int APR_KILL_ALWAYS = 1;
	/**
	 * SIGTERM, wait 3 seconds, SIGKILL
	 */
	public static final int APR_KILL_AFTER_TIMEOUT = 2;
	/**
	 * wait forever for the process to complete
	 */
	public static final int APR_JUST_WAIT = 3;
	/**
	 * send SIGTERM and then wait
	 */
	public static final int APR_KILL_ONLY_ONCE = 4;

	public static final int APR_PROC_DETACH_FOREGROUND = 0;
	/**
	 * Do not detach
	 */
	public static final int APR_PROC_DETACH_DAEMONIZE = 1;
	/**
	 * Detach
	 */

    /* Maximum number of arguments for create process call */
	public static final int MAX_ARGS_SIZE = 1024;
	/* Maximum number of environment variables for create process call */
	public static final int MAX_ENV_SIZE = 1024;

	/**
	 * Allocate apr_proc_t structure from pool
	 * This is not an apr function.
	 *
	 * @param cont The pool to use.
	 */
	public static native long alloc(long cont);

	/**
	 * This is currently the only non-portable call in APR.  This executes
	 * a standard unix fork.
	 *
	 * @param proc The resulting process handle.
	 * @param cont The pool to use.
	 * @return APR_INCHILD for the child, and APR_INPARENT for the parent
	 * or an error.
	 */
	public static native int fork(long[] proc, long cont);

	/**
	 * Create a new process and execute a new program within that process.
	 * This function returns without waiting for the new process to terminate;
	 * use apr_proc_wait for that.
	 *
	 * @param progname The program to run
	 * @param args     The arguments to pass to the new program.  The first
	 *                 one should be the program name.
	 * @param env      The new environment table for the new process.  This
	 *                 should be a list of NULL-terminated strings. This argument
	 *                 is ignored for APR_PROGRAM_ENV, APR_PROGRAM_PATH, and
	 *                 APR_SHELLCMD_ENV types of commands.
	 * @param attr     The procattr we should use to determine how to create the new
	 *                 process
	 * @param pool     The pool to use.
	 * @return The resulting process handle.
	 */
	public static native int create(long proc, String progname,
	                                String[] args, String[] env,
	                                long attr, long pool);

	/**
	 * Wait for a child process to die
	 *
	 * @param proc    The process handle that corresponds to the desired child process
	 * @param exit    exit[0] The returned exit status of the child, if a child process
	 *                dies, or the signal that caused the child to die.
	 *                On platforms that don't support obtaining this information,
	 *                the status parameter will be returned as APR_ENOTIMPL.
	 *                exit[1] Why the child died, the bitwise or of:
	 *                <PRE>
	 *                APR_PROC_EXIT         -- process terminated normally
	 *                APR_PROC_SIGNAL       -- process was killed by a signal
	 *                APR_PROC_SIGNAL_CORE  -- process was killed by a signal, and
	 *                generated a core dump.
	 *                </PRE>
	 * @param waithow How should we wait.  One of:
	 *                <PRE>
	 *                APR_WAIT   -- block until the child process dies.
	 *                APR_NOWAIT -- return immediately regardless of if the
	 *                child is dead or not.
	 *                </PRE>
	 * @return The childs status is in the return code to this process.  It is one of:
	 * <PRE>
	 * APR_CHILD_DONE     -- child is no longer running.
	 * APR_CHILD_NOTDONE  -- child is still running.
	 * </PRE>
	 */
	public static native int wait(long proc, int[] exit, int waithow);

	/**
	 * Wait for any current child process to die and return information
	 * about that child.
	 *
	 * @param proc    Pointer to NULL on entry, will be filled out with child's
	 *                information
	 * @param exit    exit[0] The returned exit status of the child, if a child process
	 *                dies, or the signal that caused the child to die.
	 *                On platforms that don't support obtaining this information,
	 *                the status parameter will be returned as APR_ENOTIMPL.
	 *                exit[1] Why the child died, the bitwise or of:
	 *                <PRE>
	 *                APR_PROC_EXIT         -- process terminated normally
	 *                APR_PROC_SIGNAL       -- process was killed by a signal
	 *                APR_PROC_SIGNAL_CORE  -- process was killed by a signal, and
	 *                generated a core dump.
	 *                </PRE>
	 * @param waithow How should we wait.  One of:
	 *                <PRE>
	 *                APR_WAIT   -- block until the child process dies.
	 *                APR_NOWAIT -- return immediately regardless of if the
	 *                child is dead or not.
	 *                </PRE>
	 * @param pool    Pool to allocate child information out of.
	 */
	public static native int waitAllProcs(long proc, int[] exit,
	                                      int waithow, long pool);

	/**
	 * Detach the process from the controlling terminal.
	 *
	 * @param daemonize set to non-zero if the process should daemonize
	 *                  and become a background process, else it will
	 *                  stay in the foreground.
	 */
	public static native int detach(int daemonize);

	/**
	 * Terminate a process.
	 *
	 * @param proc The process to terminate.
	 * @param sig  How to kill the process.
	 */
	public static native int kill(long proc, int sig);

}
